good program like photoshop?

[Team_Subspace]

that can do the "replace colors" option and is free?

 

[gameboy13]

GIMP can do this. Go to Colors > Map > Rotate Colors.

 

[zeromac]

Try GIMP, its a free alternative and is on par, if not better than photoshop

 

[Team_Subspace]

mmk thanks ill try it

 

[Infinite Zero]

GIMP or PAINT.NET although I recommend GIMP more. Don't worry, I saw the abilities of GIMP itself.

 

[Waynes1987]

I also suggest gimp, Or Google Gimp-Painter, comes with an extra brush tool for Digital drawings which is pretty awesome.

 

[SifJar]

GIMP is good, but hard to use IMO. Paint.NET is a lot simpler, but not as advanced, less tools etc. Try both and see which you like more is my advice, they're both free

 

[tenshinoneko]

Gimp =D
and if u need vectors use inkscape =D

 

[Cyan]

I like Open Canvas for replacing colors/tones.
It can read/write psd files, and have the same photoshop plugins too. It's like a light photoshop.

(It's shareware, but there's a 30day/30runs trial period. the count can be reseted anytime with correct regedit)